Time to reformat hard drive on iMac?

Question

Hi,
I have the following iMac:
Model Name:          iMac
  Model Identifier:          iMac7,1
  Processor Name:          Intel Core 2 Duo
  Processor Speed:          2.8 GHz
  Number Of Processors:          1
  Total Number Of Cores:          2
  L2 Cache:          4 MB
  Memory:          4 GB
  Bus Speed:          800 MHz
  Boot ROM Version:          IM71.007A.B03
  SMC Version (system):          1.21f4
Am running Snow Leopard.
Have had a lot of issues with rotating beach ball, slow machine performance.
When I run Verify Disk, I get the following type of errors on more or less a weekly basis:
Checking volume information.
Invalid file count
(It should be X instead of Y)
Invalid volume directory count
(It should be A instead of B)
The volume Macintosh HD was found corrupt and needs to be repaired
Error: This disk needs to be repaired...then use Disk Utility to repair this disk.
I am able to repair the disk and acheive no errors, but the cycle repeats itself in a few days.
Should I backup and reformat my hard drive?
If so, can you point me to the proper procedure please?
Thank you very much...

Answer 1

OK....very strange commentary.  Not sure what set you off, but let me add in a few additional facts that may calm you down:
This is my first Mac...purchased in 2007.  I have no Power PC programs to contend with.
I went in telling the genius guy that I probably needed a hardware fix like a new hard drive; of course I was well out of warranty.
The upgrade to OSX was NOT offered as a solution.  The Apple guy looked at my error messages, and said that based on his experience (and this is all he does all day), the problem mentioned in my initial posting above would likely be solved with an application of Disk Warrior.
He said that it was possible that this would NOT solve the problem and it could be the sign of a disk that was starting to go bad, but he said that often Disk Warrior would give a message if this were the case.
He then implemented this step.
I thanked him and then pressed him if there was anything else I could do to enhance the performance of my computer.  He then offered the prospect of upgrading to the latest operating system.
I told him that I had been reluctant to do this because I had read mixed reviews with computers my vintage.
He said that he had installed Mountain Lion on his Macbook Pro also built in 2007 but with a smaller processor thatn what I had and he liked the outcome.  We determined that my machine was already at max memory.
He started to offer me advice on how I could do the upgrade at home, said a fresh install was best. As I started to ask him more questions, he offered to do the installation for me right then and there for FREE (no software or installation cost) but double checked that I had everything backed up properly on an external hard drive.
Yes, I did have everything backed up on Time Machine back home.  He doubled checked that I wanted to proceed, so I said "Go". 
He gave me instruction on how I could uninstall Mountain Lion and revert back to Snow Leopard, if I weren't happy with the results.
So far, I am DELIGHTED with the new operating system.  I am not sure if it is the software or the fact that my disk problem appears corrected, but my machine is much, much faster.  I had been hanging on by my fingertips awaiting a new iMac, but now I feel I can perhaps get another year's worth of service out of my machine (don't you dare mention this to my wife).
It is indeed possible that my problem is not corrected...he warned me that there was the possibility that my hard drive might be ready to give up the ghost, but almost a week later, and no futher problems.
You must have had a very bad experience sometime in your history, or perhaps I was not clear in describing what happened, but from my perspective, what's not to like?  The guy was very helpful, did not charge me a cent and appears to have solved the problem.